<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div {
            background-color: pink;
            width: 1000px;
            height: 300px;
            /* margin: auto; */
        }

        /* 伪类选择器, 必须设置 content 属性，否则不生效 */
        .box1::before {
            content: "老鼠";
            width: 100px;
            height: 100px;
            background-color: brown;
            display: block;
        }

        .box1::after {
            content: "大米";
            width: 100px;
            height: 100px;
            background-color: orange;
            display: inline-block;
        }

        .box2 {
            /* border: 10px solid orange; */
            border-top: 30px solid red;
            border-left: 30px solid blue;
            border-right: 20px dotted yellow;
            border-bottom: 40px dashed purple;
            /* 边框线 */
            padding-top: 10px;
            padding-right: 20px;
            padding-bottom: 30px;
            padding-left: 40px;

        }

        .a1 {
            width: 200px;
            height: 200px;
            background-color: pink;
            margin-bottom: 10px;
        }

        .a2 {
            width: 200px;
            height: 200px;
            background-color: purple;
            margin-top: 20px;
        }

        .father {
            width: 600px;
            height: 100px;
            background-color: pink;
            padding-top: 50px;
            box-sizing: border-box;
            border-radius: 50px;
        }

        .son {
            width: 100px;
            height: 100px;
            background-color: orange;
            /* margin-top: 50px; */
        }
    </style>
</head>

<body>
    <!-- <div class="box1">爱</div> -->
    <!-- <div class="box2">div 标签</div> -->
    <!-- <div class="a1">a标签</div> -->
    <!-- <div class="a2">b标签</div> -->
    <div class="father">
        <div class="son">div 标签</div>
    </div>


</body>

</html>